Governor pressure - RA27007229150X(27-9150)
The governor pressure is derived from the working pressure and formed by the governor pressure system.
It acts on the command valves against the control pressure or kickdown control pressure and determines the shift point (upshifts).
The governor pressure system consists of:
- governor drive by means of helical gear (74)
- centrifugal governor (73) with control valve (a)
- and 3 flyweights each (F1, F2 and F3)
When the vehicle is stationary, the flyweights are swiveled inward and press the control valve (a) to the left. The working pressure inlet is closed and the zero discharge is open.
When the vehicle is moving, the output shaft drives the centrifugal governor. The flyweights move out and press the control valve (a) to the right.
From a speed of approx. 10 km/h the zero discharge is closed and the working pressure inlet at the control edge (c) open. The governor pressure is built up by it passing through the radial drilling (b) to the end face (d). The governor pressure pushes the control valve (a) against the force of the flyweights to the left into the control position. The working pressure inlet at the control edge (c) is restricted and the zero discharge opened in order to reduce pressure.
As vehicle speed increases, the centrifugal force rises and thus also the governor pressure. This means:
low speed = low governor pressure
high speed = high governor pressure
The pressure rise takes place in 3 stages, see diagram. The flyweights F1 and F2 are supported on the governor housing as a function of vehicle speed and thus have no effect on the further rise in pressure.